哈希返回一个动态值

Question

我碰到这个片段在RubyDocs跑了？

"#{var}" => instance_method(:do_#{var}) 

Answer 1

Dispatcher = Hash.new do |k, h| h[k] = instance_method "do_#{k}" end 

Answer 2

%w[d a v e].each_with_object({}) do |a, o| 
    o[a] = instance_method("do_#{a}") 
end 

Answer 3

Dispatcher = {} 
self.instance_methods.grep(/do_*/).each do |method| 
    Dispatcher[method.to_s.sub "do_", ""] = instance_method(method) 
end 

它通过匹配“的do_”前缀，并把它添加到Dispatcher哈希，所有实例方法迭代。